Fully threaded suture anchor with transverse anchor pin

ABSTRACT

A suture anchor has a pin that is disposed transversely within the suture anchor, over which one or more strands of suture is looped. The anchor body is threaded and has a tapered distal portion. The proximal end portion of the suture anchor body has a hexagonally shaped opening to accept a hexagonal drive head. The peripheral surface defining hexagonally shaped opening is rounded and smooth to prevent abrading sutures placed in contact therewith.

This application claims the benefit of U.S. Provisional Application No.60/559,425, filed Apr. 6, 2004, the entire disclosure of which isincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to an apparatus for anchoring surgicalsuture to bone. More specifically, the present invention relates to afully threaded suture anchor provided with a transverse anchor pin forsecuring, within the anchor, one or more strands of suture to anchor thesuture to bone during arthroscopic surgery.

When soft tissue tears away from bone, reattachment becomes necessary.Various devices, including sutures alone, screws, staples, wedges, andplugs have been used in the prior art to secure soft tissue to bone.

Recently, various types of threaded suture anchors have been developedfor this purpose. Some threaded suture anchors are designed to beinserted into a pre-drilled hole. Other suture anchors are self-tapping.

U.S. Pat. No. 4,632,100 discloses a cylindrical threaded suture anchor.The suture anchor of the '100 patent includes a drill bit at a leadingend for boring a hole in a bone, followed by a flight of threads spacedfrom the drill bit for securing the anchor into the hole created by thedrill bit.

U.S. Pat. No. 5,370,662 discloses a suture anchor having threads whichextend to the tip of the anchor. U.S. Pat. No. 5,156,616 discloses asimilar suture anchor having an axial opening for holding a knottedpiece of suture.

All of the above-noted suture anchors include structure for attachingthe suture to the anchor. U.S. Pat. No. 4,632,100, for example,discloses a press-fitted disc and knot structure which secures thesuture to the anchor. In other suture anchors, such as those disclosedin U.S. Pat. No. 5,370,662, the suture is passed through an eyeletlocated on the proximal end of the anchor. In the case of abioabsorbable suture anchor, the suture may be insert molded into theanchor, as disclosed in U.S. Pat. No. 5,964,783.

Problems can arise if the structure for attaching the suture fails,allowing the suture to become detached from the anchor. Also, the sutureoften is exposed to abrasion or cutting by sharp or rough areas alongthe walls of the bone canal into which the anchor is inserted.

Moreover, the eyelet or, in the case of U.S. Pat. No. 4,632,100, theaxial opening for receiving the disc to which the suture is knotted, isformed as part of the drive head of the known suture anchors. Combiningthese two functions in one structure often tends to weaken the drivehead.

In addition, various other modifications to the drive head often areemployed in connection with suture attachment. For example, recessedgrooves may be formed on opposite sides of the drive head to receive andprotect the suture from abrasive areas of the suture anchor tunnel or tofacilitate mating between the anchor to the driver. In such cases, thedrive head often must be made of a larger diameter to recover themechanical strength lost from the removal of material relating to thesuture-attachment or suture-protection modifications.

Further, the prior art suture anchors having eyelets extending from theproximal ends require countersinking of the eyelet below the bonesurface to avoid having the patient's tissue abrade against the exposedeyelet. As a result, suture attached to the eyelet is vulnerable toabrasion by the bony rim of the countersunk hole into which the sutureanchor is installed. In addition, in biodegradable suture anchors, thesuture eyelet can degrade rapidly, causing the suture to become detachedfrom the anchor prematurely.

Accordingly, there is a need for a threaded suture anchor to whichsuture is secured effectively so as to prevent detachment of the suture.It is further desirable for such suture anchors to have eyelets thatwill not abrade tissue and which do not require countersinking.

SUMMARY OF THE INVENTION

The suture anchor of the present invention overcomes the disadvantagesof the prior art discussed above by providing a threaded suture anchorhaving a tranverse anchor pin disposed inside the body of the sutureanchor. The suture anchor is made of a biocompatible metal, preferably atitanium alloy.

The proximal end surface of the threaded suture anchor of the presentinvention is preferably smooth and rounded to minimize suture abrasion,while the distal portion of the anchor is tapered to an elongated pointto enable the anchor to be self-tapping. The proximal end portion of thesuture anchor body has a hexagonally shaped opening to accept ahexagonal drive head.

The internal transverse pin provides a support over which one or morestrands of suture can be looped, such that the suture is secured in arecessed fashion within the anchor.

Advantageously, suture attached to the anchor through the transverse pinexits the suture anchor through a central bore in the anchor, whichprevents suture abrasion by the wall of the bone tunnel into which theanchor is inserted.

Other features and advantages of the present invention will becomeapparent from the following description of the invention, which refersto the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the suture anchor of the presentinvention.

FIG. 2 is a longitudinal sectional view of the suture anchor shown inFIG. 1 through the plane D-D indicated therein.

FIG. 3 is a proximal end view of the suture anchor of FIG. 1.

FIG. 4 is a cross sectional view of the suture anchor of FIG. 1 showinga suture looped over the transverse anchor pin.

FIG. 5 is a cross sectional view of the suture anchor of FIG. 1 showinga portion of a hex driver inserted into a hexagonally shaped bore.

FIG. 6 is a cross sectional view of the suture anchor of FIG. 1 showingmore of the hex driver inserted into a hexagonally shaped bore.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following detailed description, reference is made to variousspecific embodiments in which the invention may be practiced. Theseembodiments are described with sufficient detail to enable those skilledin the art to practice the invention, and it is to be understood thatother embodiments may be employed, and that structural and logicalchanges may be made without departing from the spirit or scope of thepresent invention.

FIG. 1 illustrates a suture anchor according to a first preferredembodiment of the present invention, indicated generally by referencenumeral 110. In the preferred embodiment, body 108 of anchor 110generally tapers to a narrow point 114 at the distal end thereof. Inparticular, the major diameter of the anchor body is generally constantalong about two-thirds of the length of the body, whereupon the diameterof the anchor then tapers to a relatively sharp point, e.g.,approximately 16°. The relatively sharp distal tip of anchor 110 enablesthe anchor to be installed without having to first drill a hole in thebone where the anchor 110 is to be installed.

Although such tapering is preferred, suture anchor 110 may be formed tohave a less tapered shape, or even cylindrical shape, to accommodatedifferent preferences of the surgeon and/or the application of thesuture anchor. For example, the tapered distal end of the anchor may beformed to be more blunt, in which case it is necessary to provide apre-formed hole in the bone prior to insertion of the suture anchor.

A continuous thread 116 wraps around the body 108 in a clockwisedirection, as shown. Anchor 110 has about five flights of thread, withthe angle of the threads and other configurations of the anchor beingsimilar to the suture anchor of U.S. Pat. No. 6,511,499, the disclosureof which is hereby incorporated by reference in its entirety.

As can be seen more clearly with reference to FIG. 2, the proximal endportion of the anchor has a hexagonally shaped bore 132 having anopening 122 at the proximal end of anchor body 108 and extending intothe anchor body approximately one-third of the length thereof. Prior artanchors have sharp edges around the drive opening, which is problematicin that sutures passing through the central opening at the proximal endof the anchor can be abraded by the sharp edges, thereby compromisingthe strength of the sutures. The hexagonally shaped bore 132 includes atleast two internal faces (not numbered). The two internal facesintersect obliquely relative to each other. In one example, there aresix internal planar faces. In the suture anchor of the presentinvention, the peripheral edges defining hexagonally shaped opening 122is smooth and rounded outwardly with no sharp edges. Preferably, theopening 122 forms a slight lip curving around the diameter of the bore132. Thus, sutures threaded through the anchor 110, as will be discussedbelow, will not become frayed upon being pressed or rubbed against theanchor at the proximal opening 122.

A cylindrical bore 136 having a diameter corresponding to that of thehexagonally shaped bore 132 extends from the distal end of thehexagonally shaped bore 132 to a position roughly halfway along thelength of anchor body 108. The transition between hexagonally shapedbore 132 and cylindrical bore 136 forms an annular shoulder 134, againstwhich the distal end 214 of a hex driver 202 abuts when inserted intothe hexagonally shaped bore 132 to drive the anchor into bone.

Two longitudinal, diametrically opposite apertures 118 are formed inanchor body 108, the apertures 118 supporting a metal transverse anchorpin 120 which extends across cylindrical bore 136.

As can be seen in FIGS. 1, 2 and 4, apertures 118 extend through andinterrupt the threads 116 around anchor body 108 at approximatelyone-third of the length of the anchor body from the distal end thereof.One or more sutures 200 are secured to the anchor by looping thesuture(s) around metal anchor pin 120 as shown in FIG. 4. Although themetal anchor pin 120 is illustrated in FIGS. 2 and 4 as orientedtransversal to longitudinal axis 150 of the anchor body 108, the metalanchor pin 120 may form any angle with the longitudinal axis 150 and,thus, the invention is not limited to metal anchor pin 120 forming anangle of about ninety degrees with the longitudinal axis 150 of theanchor body 108.

Preferably, suture anchor 110 is formed of a hard biocompatible metal,such as a titanium alloy, but can be made of biocompatible materialsother than metal. The suture secured to the anchor may be FiberWiresuture, sold by Arthrex, Inc. of Naples, Fla.

The suture anchor according to the present invention need not be formedas a threaded device, but can also be formed as a tap-in type anchor.Also, the measurements, angles and ratios between the dimensions of thesuture anchor may be varied from those described above so as to besuitable for the conditions and applications in which the suture anchoris to be used.

In manufacturing the suture anchor 110 in accordance with the presentinvention, the anchor body 108 is cast in a die, with the bores,passageways and apertures described above either being formed during thecasting process or formed afterwards. If necessary, the distal tip 114of the anchor 110 is trimmed to the desired length and the surfaces ofthe anchor are polished to the desired finish.

As mentioned above, the suture anchor of the present invention may beinstalled in the bone without the need to pre-drill a hole in the bone.The suture anchor is installed using a driver having a shaft having ahexagonal cross-section for at least a length equal to the length of thehexagonal bore 132 from proximal opening 122 to the shoulder 134 insidethe anchor 110. The driver has a cannula extending through the entirelength thereof, with openings at the proximal and distal ends thereof.Of course, the outer diameter of the hexagonal shaft is sized to fitinside the hexagonal bore in the anchor so as to be enabled to drive thesame.

As shown in FIGS. 5 and 6, the desired number of suture strands 200threaded around the anchor pin 120 in the suture anchor 110, the ends206 and 208 of the suture strands 200 are threaded through the cannula204 in the hex driver 202 from the distal end 214 thereof and extendfrom the proximal opening 216 thereof. The distal end 214 of the hexdriver 202 is inserted into the proximal end of the anchor 110. With thedistal end 214 of the hex driver 202 abutting the shoulder 134 and theanchor 110 positioned at the location at which it is to be installed,the hex driver 202 is rotated to drive the anchor 110 into the boneuntil the proximal surface of the anchor 110 is flush with the surfaceof the bone.

Since it is not necessary for the proximal end of the anchor to becountersunk below the bone surface to prevent tissue abrasion by anexposed suture loop, as is required with prior art devices, the sutureanchor of the present invention does not need to be inserted as far asthe prior art anchors, while also avoiding abrasion of the sutures bythe rim of the bone.

The suture anchor of the present invention provides greater pull-outstrength of the suture loop than prior suture anchors. In addition, thesuture loop of the present invention, being disposed inside the sutureanchor, is protected from abrasion and degradation.

Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art.Therefore, the present invention is to be limited not by the specificdisclosure herein, but only by the appended claims.

1. A suture anchor assembly for attachment of tissue to bone, the sutureanchor assembly comprising: an anchor body including a distal end, aproximal end, a longitudinal axis, an outer surface and a central bore,the central bore being located at the proximal end and extendingpartially through the anchor body; a rigid member having a longitudinalaxis and disposed in the central bore, wherein the longitudinal axis ofthe rigid member extends across the longitudinal axis of the anchorbody; at least one tissue securing suture looped around the rigid memberincluding a first end and a second end, wherein the first end and thesecond end of the at least one tissue securing suture extend out of theanchor body and extend out of an opening at the proximal end of theanchor body; and a driver having a cannula, wherein the driver isreceived in a portion of the central bore, wherein the cannula has adistal opening and a proximal opening, wherein the first end and thesecond end of the at east one tissue securing suture extend out of theproximal opening of the cannula.
 2. The suture anchor assembly accordingto claim 1, wherein the anchor body is metal.
 3. The suture anchorassembly according to claim 1, wherein the rigid member is metal.
 4. Thesuture anchor assembly according to claim 1, wherein the anchor body istapered.
 5. The suture anchor assembly according to claim 1, wherein theanchor body is self-tapping.
 6. The suture anchor assembly according toclaim 1, wherein the anchor body comprises a plurality of threadsextending from the outer surface of the anchor body, and the pluralityof threads extend to the proximal end of the anchor body.
 7. The sutureanchor assembly as recited in claim 1, wherein the central bore includesa first section and a second section, the first section accommodates thedriver, and the rigid member is disposed in the second section.
 8. Thesuture anchor assembly according to claim 7, wherein the first sectionhas a hexagonally shaped cross section, the second section iscylindrical, and the at least one tissue securing suture is loopedaround and contacts the rigid member in the second section of thecentral bore.
 9. The suture anchor assembly according to claim 1,wherein the central bore has a cross-sectional shape so as toaccommodate the driver for driving the anchor body, the central boreincludes a plurality of contact surfaces for the driver, the pluralityof contact surfaces including a first planar face and a second planarface, and the first planar face and the second planar face intersectalong the longitudinal axis of the anchor body.
 10. The suture anchorassembly according to claim 9, wherein the central bore includes a firstsection and a second section, the first section includes the firstplanar face and the second planar face that accommodates the driver, andthe rigid member is disposed in the second section.
 11. The sutureanchor assembly according to claim 10, wherein the first section has ahexagonally shaped cross section and the second section is cylindrical,and the at least one tissue securing suture is looped around andcontacts the rigid member in the second section of the central bore. 12.The suture anchor assembly according to claim 9, wherein the firstplanar face and the second planar face are generally parallel to thelongitudinal axis of the anchor body.
 13. The suture anchor assembly asrecited in claim 1, wherein the central bore has a cross-sectional shapeso as to accommodate the driver for driving the suture anchor.
 14. Thesuture anchor assembly as recited in claim 1, wherein the longitudinalaxis of the rigid member is transverse to the longitudinal axis of theanchor body.
 15. The suture anchor assembly as recited in claim 14,wherein the longitudinal axis of the rigid member is generallyperpendicular to the longitudinal axis of the anchor body.
 16. Thesuture anchor assembly as recited in claim 1, wherein the first end ofthe at least one tissue securing suture is unattached to the second endof the at least one tissue securing suture.
 17. The suture anchorassembly as recited in claim 1, wherein the first end of the at leastone tissue securing suture is free to move relative to the second end ofthe at least one tissue securing suture.
 18. The suture anchor assemblyas recited in claim 1, wherein the first end is a first loose end of theat least one tissue securing suture and the second end is a second looseend of the at least one tissue securing suture.
 19. The suture anchorassembly as recited in claim 1, wherein the at least one tissue securingsuture is slidably releasable from the rigid member.
 20. The sutureanchor assembly according to claim 1, wherein the rigid member isstraight.